GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"7444 results found.
- EP241202b: KAIT optical upper limit
- LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
- EP241202b: Kinder optical counterpart candidate
- EP241201a: NOT optical observations
- EP241201a: Kinder optical counterpart candidate
- LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
- LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
- LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241130be: Updated Sky localization
- LIGO/Virgo/KAGRA S241130n: Updated Sky localization
- LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
- LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
- LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
- LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
- LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
- LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
- EP241126a: WFST Observations
- GRB 241127A: Swift detection of a burst with an optical counterpart
- LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
- LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
- IceCube-241127A: IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
- LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
- LIGO/Virgo/KAGRA S241126dm: Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
- LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
- LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
- LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
- LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
- LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
- LIGO/Virgo/KAGRA S241125n: Updated Sky localization
- LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
- LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
- LIGO/Virgo/KAGRA S241109bn: Upper limits from a two-week IceCube neutrino search
- LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
- LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
- LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification
- LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate
- GRB241120A: OHP/T193 optical observations
- GRB 241120A: Mondy and AbAO optical observations
- GRB 241112B: Mephisto further optical observations
- LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S241114y: Updated Sky localization
- Updates to IceCube realtime alert system for muon tracks
- LIGO/Virgo/KAGRA S241116cq: Updated Sky localization
- LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
- GRB 241113B: Mephisto upper limits
- LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S241113p: Updated Sky localization
- EP241113a: No Detection in Fermi-GBM Observations
- GRB 241115A: Swift detection of a burst
- EP 241113a: LBT possible optical counterpart
- GRB 241113B: KAIT Optical Afterglow Candidate
- LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
- Konus-Wind detection of GRB 241107A (short/hard)
- LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
- GRB 241113B: Swift ToO observations
- IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
- GRB 241112B: LCO optical detection of the SVOM/VT candidate
- GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
- GRB 241112B: Mephisto optical upper limits
- GRB 241112B: Swift ToO observations
- LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
- LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241110br: Updated Sky localization
- LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
- LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
- LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
- GRB 241108A: Swift ToO observations
- EP241107a: Kinder optical follow-up observations
- EP241101a: CrAO ZTSH optical observations
- LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
- LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
- GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
- GRB 241105A: Swift ToO observations
- GRB 241104A: Swift ToO observations
- GRB 241104A: NOT optical non-detection
- GRB 241105A: GOTO tentative optical counterpart candidate
- GRB 241104A: SVOM/VT optical candidate
- EP241101a: EP-FXT observations update
- LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
- LIGO/Virgo/KAGRA S241102br: Updated Sky localization
- EP241101a: Optical upper limits with Kinder observations